This event will check the tempvar value (which in this case is 0 because it is undefined from the start) unit, if it is a HQ. I think you have set it to do something, in case it is not, but I never used this function so i really don´t know.

If the unit is NOT a HQ, it will give -70 readiness to unit 0 (that is the unit you have chosen) and all the people in that unit, that are SFT 6.